<!--
 * @Author: your name
 * @Date: 2021-08-09 11:09:05
 * @LastEditTime: 2021-08-15 21:50:06
 * @LastEditors: Please set LastEditors
 * @Description: In User Settings Edit
 * @FilePath: \第一周\3-tyut.html
-->
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>太原理工大学</title>
    <style>
        ul,p,body {
            margin: 0px;
            padding: 0px;
        }
        /* 一级菜单容器 */
        ul.menu {
            background-color: tomato;
            color: #fff;
        }
        ul.menu::after {
            content: "";
            display: block;
            clear: both;
        }
        /* 一级菜单元素 */
        ul.menu > li.menu_item {
            float: left;
            width: 100px;
            line-height: 3em;
            text-align: center;
            position: relative;
            cursor: pointer;
        }
        /* 二级菜单元素 */
        ul.menu > li.menu_item:hover ul.sub_menu {
            display: block;
        }
        ul.menu ul.sub_menu {
            display: none;
            position: absolute;
            color: #666;
        }

        /* 三级菜单元素 */
        ul.menu > li.menu_item > ul.sub_menu > li {}
        ul.menu ul.sub_menu > li {}
    </style>
</head>
<body>
    <div class="tyut">
        <!-- 头部 -->
        <header>
            <div class="first_line"></div>
            <div class="second_line">
                <div class="logo">logo</div>
                <!-- ul 菜单列表 -->
                <ul class="menu">
                    <li class="menu_item">
                        <span>学校概况</span>
                        <ul class="sub_menu">
                            <li>学校简介</li>
                            <li>历史沿革</li>
                        </ul>
                    </li>
                    <li class="menu_item">
                        <span>人才培养</span>
                        <ul class="sub_menu">
                            <li>本科生教育</li>
                            <li>研究生教育</li>
                        </ul>
                    </li>
                    <li class="menu_item">
                        <span>科学研究</span>
                    </li>
                </ul>
            </div>
            <div class="second_line"></div>
        </header>
    </div>
</body>
</html>
